[dm-crypt] Bug Report to Ubuntu regarding dangerous installer

Claudio Moretti flyingstar16 at gmail.com
Sat Apr 16 13:06:48 CEST 2011

> > > As far as I know (I'm an Ubuntu user, with a little experience) you can
> > choose between automatic and manual partitioning; partitioning options
> are
> > shown here: https://help.ubuntu.com/community/GraphicalInstall and the
> > partition step in the installation process is fully described here:
> >
> https://help.ubuntu.com/10.10/installation-guide/i386/module-details.html#di-partition
> >
> > If you choose automatic partitioning, you will lose the content of your
> > disks, but the system warns you; if you choose manual partitioning and
> > delete the dm-crypt partitions to make new ones, I don't see how the
> > installer can warn you, aside from telling you you're destroying a
> partition
> > (and if you choose manual partitioning, you should know what can happen,
> > otherwise you shouldn't use it).
> >
> > In order to use encrypted disks, the installer needs to write the
> partition
> > table: before doing it, it warns you that when writing the partition
> table
> > changes will be written on the disk and you may lose your data.
> Huh? Why does it need to write the partition table? LUKS causes
> no such requirement...

The alternate installer provides you with a "Prepare encrypted disks" option
(something like this, I don't remember the exact name); You create your
partitions and select the "physical volume for encryption" filesystem type ;
then you choose the "Prepare encrypted disk" option and the installer writes
the partition table, asks for which partitions you want to encrypt and makes
you choose passphrases.
Then it shows you new "disks" that are your encrypted partitions; inside of
those "disks" you can create your ext{2,3,4}/FAT/ReiserFS/etc. partitions
(screenshot of what I mean, taken from Google Images:
I think this happens because the right partitions are needed to use the
device mapper and create filesystems in which the system can be installed

> > In _my_ opinion, the process is quite clear. I see that there may be
> > problems, but, well (and with this I don't mean to offend anybody,
> because I
> > made really stupid mistakes with encrypted partitions) if you don't read
> > what you're doing, it's not an Ubuntu problem; like if you type that
> > uppercase YES while luksFormat-ting a partition and then complain that it
> > should have warned you better...
> I think this is something else. But I would not know.
> Then I don't know, either. But I think that when choosing the alternate
installer (which is more advanced than the graphical one) you should know
you're using an "expert" tool..
I'm attaching a few screenshot I found on GI of what the installer does

Main menu:
Main menu (manual partitioning):
Partition usage list:
Partitioning confirmation:
Partition schema with dm-crypt and LVM:

Hope this may help.

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